An elongate hadrosaurid forelimb with biological traces informs the biogeography of the Lambeosaurinae

Abstract

Although the fossil record of the Late Cretaceous eastern North American landmass Appalachia is poor compared to that from the American West, it includes material from surprisingly aberrant terrestrial vertebrates that may represent relictual forms persisting in relative isolation until the end of the Mesozoic. One intriguing question is to what extent eastern and western North American faunas interspersed following the closure of the Western Interior Seaway during the Maastrichtian Stage of the Late Cretaceous ca. 70 Ma. Isolated remains from the Atlantic Coastal Plain in New Jersey have been preliminarily identified as the bones of crested lambeosaurine hadrosaurids, a derived clade known from the Cretaceous of Asia, western North America, and Europe, but have not been formally described. We describe the partial forelimb of a large hadrosaurid from the late Maastrichtian New Egypt Formation of New Jersey. The ulna preserves multiple deep scores identifiable as shark feeding marks, and both bones show ovoid and circular marks attributable to invertebrates. This forelimb is very similar to another partial antebrachium from the same area that shows evidence of septic arthritis. Both these specimens and a complete humerus from the same unit are closely comparable to the lower forelimbs of lambeosaurines among hadrosaurid dinosaurs. Although the absence of lambeosaurine synapomorphies observable on the New Egypt Formation forelimbs precludes their definite referral to Lambeosaurinae, they show that a morphotype of large hadrosauromorph with distinctly elongate forelimbs existed in the latest Maastrichtian of eastern North America and allow for a revision of the latest Cretaceous biogeography of crested herbivorous dinosaurs.

Dinosaurs from the Santonian–Campanian Atlantic coastline substantiate phylogenetic signatures of vicariance in Cretaceous North America

“…The description of a potentially novel hadrosaurid from the Santonian-Campanian of the Atlantic coastline also evidences the similarity of Late Cretaceous dinosaur faunas from Appalachia and Eurasia. Previous comparisons of Appalachian and Eurasian vertebrate assemblages highlighted the similarity of lambeosaurine, kogaionid, marsupial and crocodyliform fossils from these regions [117,127,128], but the low number of associated skeletons from Appalachia precluded testing these similarities under a phylogenetic framework. Putative Appalachian records of some of these clades, including the Lambeosaurinae, may also not show clear affinities to those groups [129].…”

Dispersal sweepstakes: Biotic interchange propelled air‐breathing fishes across the globe

“…The proliferation of molecular data for phylogenetic analysis has drastically altered the resolution of the fish Tree of Life and provided a wealth of time‐calibrated phylogenies that can be used to re‐examine longstanding assumptions about freshwater fish biogeography (Dornburg & Near, 2021). For example, time‐calibrated molecular phylogenies have both corroborated and contradicted long held assumptions of Gondwanan continental vicariance of lungfishes (Brownstein et al., 2023) and cichlids (Friedman et al., 2013; Matschiner et al., 2020), respectively. The rapidly emerging molecular phylogenetic perspective of fish systematics highlights the need to continuously reassess biogeographical hypotheses of the origins of freshwater fish diversity.…”

Evolution of Hadrosaurs in the Campanian of Laramidia: New Information from the Skull Roof and Braincase

“…Hollow-crested hadrosaurs, belonging to the clade Lambeosaurinae, were widely distributed across the northern hemisphere towards the end of the Cretaceous (Horner et al 2004;Brownstein and Bissell 2021;Longrich et al 2021).…”